The article from the newspaper didn't mention Harleys, just motorcycles in general. You decided that it must have been Harleys. Why didn't you mention sport bikes or 6 into 6 pipes? They are just as loud.
Well, my experience has been that of the LOUD bikes I hear, really loud, not just a little loud, AT LEAST 90% of them are Harleys. Your experience may differ.
MP